Mantisbt · Mantisbt · CVE-2026-39960
**Name of the Vulnerable Software and Affected Versions**
Mantis Bug Tracker (MantisBT) versions prior to 2.28.2
**Description**
Flawed logic in the Update Issue page 'bug update page.php' causes improper escaping of textarea custom field contents. This allows an authenticated user with low-privilege bug report permissions to inject HTML and potentially execute arbitrary JavaScript if Content-Security Policy (CSP) settings permit. Such execution can lead to session theft, administrative account takeover, and unauthorized access to full project data. Exploitation requires a textarea-type custom field to be configured for the project and affects any user viewing the bug edit form, including administrators.
**Recommendations**
Update to version 2.28.2.
Use the default Content-Security Policy to block script execution as a temporary workaround.